Forecasting Periodic Trends: A Semester-Long Team Exercise for Nonscience MajorsJohn TierneyTeams of students in a course for nonscience majors identify trends among the properties of elements in the periodic table, use Excel to plot and produce best-fit equations to describe relationships among those properties, and apply the resulting formulas to predict and justify the properties of missing elements.Tierney, John. J. Chem. Educ.2008, 85, 1215.

Atomic Properties / Structure |

Computational Chemistry |

Main-Group Elements |

Nonmetals |

Periodicity / Periodic Table |

Metals |

Student-Centered Learning

Trends in Ionization Energy of Transition-Metal ElementsPaul S. MatsumotoExamines why, as the number of protons increase along a row in the periodic table, the first ionization energies of the transition-metal elements are relatively steady, but that for the main-group elements increases.Matsumoto, Paul S. J. Chem. Educ.2005, 82, 1660.

Atomic Properties / Structure |

Periodicity / Periodic Table |

Transition Elements

E = mc2 for the Chemist: When Is Mass Conserved?Richard S. TreptowEinstein's famous equation is frequently misunderstood in textbooks and popular science literature. Its correct interpretation is that mass and energy are different measures of a single quantity known as massenergy, which is conserved in all processes.Treptow, Richard S. J. Chem. Educ.2005, 82, 1636.

Response to Lowe's Potential-Energy-Only ModelsLowe, John P.Discussion of the suitability of a potential-only model for the successive ionization energies of sulfur for an introductory chemistry course.Lowe, John P. J. Chem. Educ.2002, 79, 430.

The Mendeleev-Seaborg Periodic Table: Through Z = 1138 and BeyondPaul J. KarolExtending the periodic table to very large atomic numbers and its implications for the organization of the periodic table, consideration of relativistic effects, and the relative stability of massive and supermassive atomic nuclei.Karol, Paul J. J. Chem. Educ.2002, 79, 60.

Ionization Energies, Parallel Spins, and the Stability of Half-Filled ShellsPeter CannThree methods for explaining the decrease in first ionization energies between group V and group VI elements are described and commented upon. The quantum mechanical origin of the unhelpful concept of half-shell stability is explained in terms of exchange energy, for which the alternative term parallel spin avoidance factor is suggested. It is recommended that for pre-university students the simplest explanation, in terms of Coulombic repulsion between two electrons occupying the same orbital, is adopted: it involves fewer difficult concepts than the other explanations and its predictions are no less accurate. Cann, Peter. J. Chem. Educ.2000, 77, 1056.

Atomic Properties / Structure |

Periodicity / Periodic Table |

Quantum Chemistry |

Theoretical Chemistry

Chemistry of the Heaviest Elements-One Atom at a TimeDarleane C. Hoffman and Diana M. LeeA 75-year perspective of the chemistry of the heaviest elements, including a 50-year retrospective view of past developments, a summary of current research achievements and applications, and some predictions about exciting, new developments that might be envisioned within the next 25 years.Hoffman, Darleane C.; Lee, Diana M. J. Chem. Educ.1999, 76, 331.

Chromatography |

Instrumental Methods |

Isotopes |

Nuclear / Radiochemistry |

Separation Science |

Descriptive Chemistry |

Enrichment / Review Materials |

Atomic Properties / Structure

The Gravity of the SituationDamon DiementeThis article presents a few calculations demonstrating that gravitational attraction between atoms is many orders of magnitude weaker than the gravitational attraction between Earth and an atom, and that the gravitational attraction between two ions is many orders of magnitude weaker than the electromagnetic attraction between them. Diemente, Damon. J. Chem. Educ.1999, 76, 55.

Atomic Properties / Structure |

Covalent Bonding |

Noncovalent Interactions

Modeling Nuclear Decay: A Point of Integration between Chemistry and MathematicsKent J. Crippen and Robert D. CurtrightA four-part activity utilizing a graphing calculator to investigate nuclear stability is described. Knowledge acquired through the activity provides background for answering the societal question of using nuclear materials for energy production. Crippen, Kent J.; Curtright, Robert D. J. Chem. Educ.1998, 75, 1434.

Nuclear / Radiochemistry |

Atomic Properties / Structure |

Chemometrics

Electron Affinities of the Alkaline Earth Metals and the Sign Convention for Electron AffinityJohn C. WheelerIt has been known since 1987, both theoretically and experimentally, that the ion Ca- is stable. It is now certain that Sr-, Ba-, and Ra- are also stable, and accurate values for the electron affinities of Ca-, Sr-, and Ba- have been determined. Recommended values for these electron affinities, in the units commonly employed in introductory texts and with the sign convention used here, are 2.37, 5.03, and 13.95 kJ/mol for Ca, Sr, and Ba, respectively. Wheeler, John C. J. Chem. Educ.1997, 74, 123.

Moseley's Work on X-Rays and Atomic NumberC. W. HaighExplanation of the relationship between Moseley's work in determining atomic numbers, the spectrum of the hydrogen atom, the Bohr theory, and Slater's rules for screening constants.Haigh, C. W. J. Chem. Educ.1995, 72, 1012.

The periodicity of electron affinityMyers, R. ThomasIn general, the values of electron affinity for the elements can be understood in terms of their ground state electron configuration, and the screening (effective nuclear charge) exerted on the added electron by the electrons already present in the neutral atom.Myers, R. Thomas J. Chem. Educ.1990, 67, 307.

The electronic periodic chart of the elementsvon Marttens Osorio, Hernan; Goldschmidt, AlfonsoA scheme for the arrangement of the elements that allows students to understand and write down the electronic configuration of any given element.von Marttens Osorio, Hernan; Goldschmidt, Alfonso J. Chem. Educ.1989, 66, 758.

Periodicity / Periodic Table |

Atomic Properties / Structure

What is an element?Roundy, Willard H., Jr.Problems with using outdated definitions of what constitutes an element.Roundy, Willard H., Jr. J. Chem. Educ.1989, 66, 729.

Isotopes |

Atomic Properties / Structure

Principles of electronegativity Part I. General natureSanderson, R. T.The concept of electronegativity has been modified, expanded, and debated. The concept can be used to help students gain valuable insights and understanding of the cause-and-effect relationship between atomic structure and compound properties. This is the first in a series of articles that explores the important concept of electronegativity.Sanderson, R. T. J. Chem. Educ.1988, 65, 112.

But if atoms are so tiny...Kolb, DorisReviews the atomic theory, the laws of chemical combination, atomic weight scales, Avogadro's hypothesis, the development of the mass spectrograph, the meaning of atomic weight, and the difference between mass and weight in answering the question "If atoms are so small, how can we know how much they weigh?" [Debut]Kolb, Doris J. Chem. Educ.1977, 54, 543.

Energy level diagrams and extranuclear building of the elementsKeller, R. N.Simplified diagrams showing the approximate order of electronic energy levels in atoms and mnemonic devices to aid in predicting electronic configurations for atoms are often misleading with respect to the actual energy of binding of the electrons in atoms and ions of the transition elements.Keller, R. N. J. Chem. Educ.1962, 39, 289.

Teaching electron configurationsEichinger, Jack W., Jr.Time can be saved and confusion avoided by developing a systematic chart of the elements based on the energy levels of atomic orbitals very early in the general college chemistry course.Eichinger, Jack W., Jr. J. Chem. Educ.1957, 34, 504.

A new periodic table based on the energy sequence of atomic orbitalsWalker, W. R.; Curthoys, G. C.Since the theory of atomic and molecular orbitals has proven to be of such value in interpreting the data of inorganic chemistry, it is hoped that a new periodic table based on the energy sequence of atomic orbitals will be an aid to the further systematizing of chemical knowledge.Walker, W. R.; Curthoys, G. C. J. Chem. Educ.1956, 33, 69.

Atomic structure and the photoelectric effectBrockett, Clyde P.The ubiquitous and inexpensive 110-volt, 2-watt neon glow lamp appears to have been overlooked as a device well suited to a brief but telling demonstration of a few key principles of atomic structure that underlie the study of electrovalence and comparative chemistry.Brockett, Clyde P. J. Chem. Educ.1953, 30, 498.

The periodic table: The 6d-5f mixed transition groupCoryell, Charles D.With relatively few modifications, the Bohr-type periodic table presented by Glocker and Popov can be made to reflect more instructively the rather complex relationships obtained in the neighborhood of the 4f or gadolinium transition group and, more importantly, in the 6d-5f sequence extending from actinium through the region of uranium and the synthetic earths to element 103.Coryell, Charles D. J. Chem. Educ.1952, 29, 62.